test: coverage recording now needs to be explicit

[mediawiki.git] / tests / phpunit / includes / cache / ProcessCacheLRUTest.php

<?php

/**
 * Test for ProcessCacheLRU class.
 *
 * Note that it uses the ProcessCacheLRUTestable class which extends some
 * properties and methods visibility. That class is defined at the end of the
 * file containing this class.
 *
 * @group Cache
 */
class ProcessCacheLRUTest extends MediaWikiTestCase {

        /**
         * Helper to verify emptiness of a cache object.
         * Compare against an array so we get the cache content difference.
         */
        function assertCacheEmpty( $cache, $msg = 'Cache should be empty' ) {
                $this->assertAttributeEquals( array(), 'cache', $cache, $msg );
        }

        /**
         * Helper to fill a cache object passed by reference
         */
        function fillCache( &$cache, $numEntries ) {
                // Fill cache with three values
                for ( $i = 1; $i <= $numEntries; $i++ ) {
                        $cache->set( "cache-key-$i", "prop-$i", "value-$i" );
                }
        }

        /**
         * Generates an array of what would be expected in cache for a given cache
         * size and a number of entries filled in sequentially
         */
        function getExpectedCache( $cacheMaxEntries, $entryToFill ) {
                $expected = array();

                if ( $entryToFill === 0 ) {
                        # The cache is empty!
                        return array();
                } elseif ( $entryToFill <= $cacheMaxEntries ) {
                        # Cache is not fully filled
                        $firstKey = 1;
                } else {
                        # Cache overflowed
                        $firstKey = 1 + $entryToFill - $cacheMaxEntries;
                }

                $lastKey = $entryToFill;

                for ( $i = $firstKey; $i <= $lastKey; $i++ ) {
                        $expected["cache-key-$i"] = array( "prop-$i" => "value-$i" );
                }

                return $expected;
        }

        /**
         * Highlight diff between assertEquals and assertNotSame
         */
        function testPhpUnitArrayEquality() {
                $one = array( 'A' => 1, 'B' => 2 );
                $two = array( 'B' => 2, 'A' => 1 );
                $this->assertEquals( $one, $two ); // ==
                $this->assertNotSame( $one, $two ); // ===
        }

        /**
         * @dataProvider provideInvalidConstructorArg
         * @expectedException MWException
         */
        function testConstructorGivenInvalidValue( $maxSize ) {
                new ProcessCacheLRUTestable( $maxSize );
        }

        /**
         * Value which are forbidden by the constructor
         */
        public static function provideInvalidConstructorArg() {
                return array(
                        array( null ),
                        array( array() ),
                        array( new stdClass() ),
                        array( 0 ),
                        array( '5' ),
                        array( -1 ),
                );
        }

        function testAddAndGetAKey() {
                $oneCache = new ProcessCacheLRUTestable( 1 );
                $this->assertCacheEmpty( $oneCache );

                // First set just one value
                $oneCache->set( 'cache-key', 'prop1', 'value1' );
                $this->assertEquals( 1, $oneCache->getEntriesCount() );
                $this->assertTrue( $oneCache->has( 'cache-key', 'prop1' ) );
                $this->assertEquals( 'value1', $oneCache->get( 'cache-key', 'prop1' ) );
        }

        function testDeleteOldKey() {
                $oneCache = new ProcessCacheLRUTestable( 1 );
                $this->assertCacheEmpty( $oneCache );

                $oneCache->set( 'cache-key', 'prop1', 'value1' );
                $oneCache->set( 'cache-key', 'prop1', 'value2' );
                $this->assertEquals( 'value2', $oneCache->get( 'cache-key', 'prop1' ) );
        }

        /**
         * This test that we properly overflow when filling a cache with
         * a sequence of always different cache-keys. Meant to verify we correclty
         * delete the older key.
         *
         * @dataProvider provideCacheFilling
         * @param $cacheMaxEntries Maximum entry the created cache will hold
         * @param $entryToFill Number of entries to insert in the created cache.
         */
        function testFillingCache( $cacheMaxEntries, $entryToFill, $msg = '' ) {
                $cache = new ProcessCacheLRUTestable( $cacheMaxEntries );
                $this->fillCache( $cache, $entryToFill );

                $this->assertSame(
                        $this->getExpectedCache( $cacheMaxEntries, $entryToFill ),
                        $cache->getCache(),
                        "Filling a $cacheMaxEntries entries cache with $entryToFill entries"
                );
        }

        /**
         * Provider for testFillingCache
         */
        public static function provideCacheFilling() {
                // ($cacheMaxEntries, $entryToFill, $msg='')
                return array(
                        array( 1, 0 ),
                        array( 1, 1 ),
                        array( 1, 2 ), # overflow
                        array( 5, 33 ), # overflow
                );
        }

        /**
         * Create a cache with only one remaining entry then update
         * the first inserted entry. Should bump it to the top.
         */
        function testReplaceExistingKeyShouldBumpEntryToTop() {
                $maxEntries = 3;

                $cache = new ProcessCacheLRUTestable( $maxEntries );
                // Fill cache leaving just one remaining slot
                $this->fillCache( $cache, $maxEntries - 1 );

                // Set an existing cache key
                $cache->set( "cache-key-1", "prop-1", "new-value-for-1" );

                $this->assertSame(
                        array(
                                'cache-key-2' => array( 'prop-2' => 'value-2' ),
                                'cache-key-1' => array( 'prop-1' => 'new-value-for-1' ),
                        ),
                        $cache->getCache()
                );
        }

        function testRecentlyAccessedKeyStickIn() {
                $cache = new ProcessCacheLRUTestable( 2 );
                $cache->set( 'first', 'prop1', 'value1' );
                $cache->set( 'second', 'prop2', 'value2' );

                // Get first
                $cache->get( 'first', 'prop1' );
                // Cache a third value, should invalidate the least used one
                $cache->set( 'third', 'prop3', 'value3' );

                $this->assertFalse( $cache->has( 'second', 'prop2' ) );
        }

        /**
         * This first create a full cache then update the value for the 2nd
         * filled entry.
         * Given a cache having 1,2,3 as key, updating 2 should bump 2 to
         * the top of the queue with the new value: 1,3,2* (* = updated).
         */
        function testReplaceExistingKeyInAFullCacheShouldBumpToTop() {
                $maxEntries = 3;

                $cache = new ProcessCacheLRUTestable( $maxEntries );
                $this->fillCache( $cache, $maxEntries );

                // Set an existing cache key
                $cache->set( "cache-key-2", "prop-2", "new-value-for-2" );
                $this->assertSame(
                        array(
                                'cache-key-1' => array( 'prop-1' => 'value-1' ),
                                'cache-key-3' => array( 'prop-3' => 'value-3' ),
                                'cache-key-2' => array( 'prop-2' => 'new-value-for-2' ),
                        ),
                        $cache->getCache()
                );
                $this->assertEquals( 'new-value-for-2',
                        $cache->get( 'cache-key-2', 'prop-2' )
                );
        }

        function testBumpExistingKeyToTop() {
                $cache = new ProcessCacheLRUTestable( 3 );
                $this->fillCache( $cache, 3 );

                // Set the very first cache key to a new value
                $cache->set( "cache-key-1", "prop-1", "new value for 1" );
                $this->assertEquals(
                        array(
                                'cache-key-2' => array( 'prop-2' => 'value-2' ),
                                'cache-key-3' => array( 'prop-3' => 'value-3' ),
                                'cache-key-1' => array( 'prop-1' => 'new value for 1' ),
                        ),
                        $cache->getCache()
                );
        }
}

/**
 * Overrides some ProcessCacheLRU methods and properties accessibility.
 */
class ProcessCacheLRUTestable extends ProcessCacheLRU {
        public $cache = array();

        public function getCache() {
                return $this->cache;
        }

        public function getEntriesCount() {
                return count( $this->cache );
        }
}